For A and b as given, the system Ax = b has no solution. Find all the least-squares solutions
A=\left[\begin{array}{rrr}1 & 0 & 2 \\0 & 2 & 2 \\-1 & 1 & -1 \\-1 & 2 & 0\end{array}\right], \quad b =\left[\begin{array}{r}3 \\-3 \\0 \\-3\end{array}\right].